Unit 5 of China's Fuqing Nuclear Power Plant, developed by CNNC [Photo/CNNC]

The unit 5 of China's Fuqing Nuclear Power Plant, developed by China National Nuclear Corporation (CNNC), reached a 'critical state' for the first time on Oct 21, indicating that the unit has officially entered a state of operation with power and has taken an important step towards completion and commissioning.

Unit 5 is the world's first pilot project to use China's indigenous third-generation nuclear power technology Hualong One, also known as HPR1000. 

Unit 5 of China's Fuqing Nuclear Power Plant, developed by CNNC [Photo/CNNC] 

The criticality of a nuclear reactor in a nuclear power plant is similar to the ignition process of a conventional thermal power plant boiler, and it is also like a heart pacemaker. After the criticality, the "heart" of the reactor - the core - will continue to "beat", and the reactor will be operating in a state of nuclear equilibrium.

Approved by the National Nuclear Safety Administration, and inspected by the Eastern Office of the National Nuclear Safety Administration, unit 5 began its reactor critical operation.

By diluting the boron concentration in the primary loop and raising the control rods, the reactor reached a critical state for the first time.

At present, CNNC's projects involving Hualong One technology is progressing in an orderly manner at home and abroad, and the safety and quality of the construction projects are under good control.

On May 5, 2015, the National Nuclear Safety Administration issued a construction permit for Fuqing Nuclear Power Plant unit 5. May 7, 2015 marked the FCD of unit 5 - the first concrete date in its construction timetable.

On Sept 10, 2020, Fuqing Nuclear Power Unit 5 successfully completed the loading of 177 sets of fuel assemblies, marking the moment that HualongOne entered the nuclear commissioning stage of the main system. 

The unit 5 of China's Fuqing Nuclear Power Plant reaches a 'critical state' for the first time on Oct 21. [Photo/CNNC]